White Papers

BP1026 Sizing MS Exchange with EqualLogicPS6100 & PS4100 on VMware vSphere 5 17
Table 6 Test results: improvement or decline relationship of performance when growing the mailbox size
512MB [500GB DB] 1GB [1TB DB] 1.5GB [1.5TB]
IOPS planned 100% [900 IOPS] 100% [900 IOPS] 100% [900 IOPS]
Total IOPS performed 100% [1530 IOPS] 90% [1383 IOPS] 92% [1413 IOPS]
Read Latency DBs 100% [7.7 msec] 106% [8.2 msec] 121% [9.3 msec]
Write Latency DBs 100% [5.2 msec] 91% [4.8 msec] 89% [4.7 msec]
Write latency LOGs 100% [1.0 msec] 97% [0.9 msec] 107% [1.0 msec]
Note: For graphing purposes, the numerical results presented in this paper have been rounded as
well as zero decimal digits for percentages and IOPS, and one digit for latencies used.
The outcomes communicate a steady behavior for write latencies closely following the trend of IOPS
dispensed. The read latencies show instead a mild, but confirmed growth while running in a scenario
with larger mailboxes. The trend is largely expected considering that in the second and third scenario
the disk surface to be reached by the drive spindle movements was doubled and then tripled. The
slight decrease in achieved IOPS is mostly due to the load generator tool, which was tuned to provide
the closest amount of workload, but performed differently in each test because of the wider amount
of data to be accessed by the working threads.
5.3 Study the database volumes layout
The goal of the database deployment layout analysis was to establish the storage trend, IOPS ratios,
and relationship while changing the number of mailbox databases (keeping SAN volume/database ratio
1:1) and maintaining the remaining factors. The configuration parameters for the test are shown in
Table 7.
Table 7 Test parameters: changing databases layout
Reference configuration: variable factor
Number of databases 2 / 5 / 10 /20 databases (active)
Databases size 1.25 TB / 500 GB / 250 GB / 125 GB each
Mailbox allocation
2,500 / 1,000 / 500 / 250
mailboxes per each mailbox database
Reference configuration: unchanged factors
Number of simulated mailboxes/users 5,000 concurrent users
Mailbox size 512 MB
Number of database replica copies 1 (standalone)
IOPS per mailbox / messages per day per mailbox 0.18 IOPS / 150 messages
RAID policy RAID 50
Array model, amount of units, SAN configuration 1x PS6100XV 3.5”, one single pool (default)
Exchange Server provides the ability to implement multiple databases on the same server with a limit
imposed by the licensed version of Exchange Server installed (a maximum of 5 databases for Exchange
Standard edition and a maximum of 100 databases for Exchange Enterprise edition). The number of